Analog circuit fault diagnosis method

Abstract

The invention discloses an analog circuit fault diagnosis method. The analog circuit fault diagnosis method comprises the steps that firstly, simulation is conducted on each element under the fault-free condition and under two fault conditions respectively, so that a fault-free voltage value and two fault voltage values of a measure point are obtained, a characteristic circle corresponding to each element is obtained according to the corresponding three voltage values, the points of intersection of the characteristic circles are obtained, so that aliasing voltages are obtained, and equivalent excitation of each element is obtained; when a circuit breaks down, the shortest distances between the fault voltage and the characteristic circles are calculated, if no more than one shortest distance is smaller than a preset threshold value, the element corresponding to the minimum shortest distance is the fault element, otherwise, the aliasing voltage which is proximal to the fault voltage is found out from all the aliasing voltages, the fault circuit is excited by means of the equivalent excitation of each element, obtained response voltage phasor sequences are compared with the characteristic circles of the corresponding elements after being moved horizontally, and the element corresponding to the highest similarity is the fault element. According to the analog circuit fault diagnosis method, point diagnosis is replaced by linear diagnosis, and the accuracy, the stability and the robustness of fault diagnosis are improved.

Description

technical field [0001] The invention belongs to the technical field of analog circuit fault diagnosis, and more specifically, relates to an analog circuit fault diagnosis method. Background technique [0002] In the current field of analog circuit fault diagnosis technology, there are two key and difficult problems to be solved. [0003] (1) Analog component parameter continuity problem. [0004] The solution to this problem is to uniformly model the continuous variation of component parameters (from zero to infinity). However, it is obvious that the commonly used open-circuit and short-circuit fault models, as well as fixed-parameter fault types (such as parameter drift up and down by 50%) and fault segment models (such as parameter changes from ±5% to ±10%) are not up to the task. In theory, the system function model can diagnose soft faults in the network. Since the system function needs to be written for fault diagnosis, there are disadvantages such as complex circuit...

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Problems solved by technology

[0006] (2) The influence of tolerance on fault diagnosis

As the scale of the circuit increases, the number of components increases, and the parameters of the non-faulty components change within the tolerance range, the resulting output signal may overwhelm the faulty signal

This problem is basically unsolvable by existing diagnostic methods (static testing of faulty circuits at one test point)

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